In the prior art, thread-wound golf balls are generally manufactured by winding a rubber thread having high elongation on a spherical liquid center to form a core ball, and then enclosing the core ball in a dimpled cover. Most liquid centers are hollow spherical center backing of rubber or the like having a hollow interior filled with water or a similar liquid containing a specific gravity modifier.
The general requirements for golf balls are an increased flying distance and ease of ball control. As compared with the two-piece golf balls, the thread-wound golf balls are increased in backspin and control but inferior in flying distance because the ball tends to lift due to the increased backspin.
There is a need for a thread-wound golf ball capable of providing a longer flying distance. It might be contemplated to increase the initial speed of the ball upon impact by increasing the impact resilience of thread rubber wound thereon. Since the initial speed of golf balls, however, is strictly restricted by the rules of the Professional Golfers, Association, a certain limit is imposed on the flying distance which can be increased by increasing the initial speed of the ball.